Wireless interface

Abstract

In one embodiment of the present invention, a wireless interface is provided for supplying all signals and power exclusively wirelessly from a transmitting section to a receiving section. The transmitting section includes a transmitter arranged to modulate a carrier with signals, such as data, control and timing signals. The transmitter is connected to a transmit antenna which comprises a parallel resonant circuit in series with a series resonant circuit. The parallel and series resonant circuits include inductors which are inductively coupled to an inductor of a receive antenna in the receiving section.

Description

TECHNICAL FIELD[0001]The present invention relates to a wireless interface. For example, such an interface may be used for supplying data and power wirelessly within a display system, for example including a flat panel display of liquid crystal or organic light emitting diode type. Another example of an application of such an interface is in a radio frequency identification system. The present invention also relates to a transmitting section and to a receiving section for such an interface.BACKGROUND ART[0002]FIG. 1 of the accompanying drawings shows a generic liquid crystal display system which is an example of a flat panel display. Such a display is made up of an active area including an active matrix 14 which displays the image, a backlight system including a driver 12 to illuminate the display and a number of driver integrated circuits (ICs) 10 to control the addressing of pixels. The system is supplied with the display data 2, a number of control and timing signals 6 and power ...

AI Technical Summary

Benefits of technology

[0032]It is thus possible to provide an arrangement which permits completely wireless interfacing of all signals and power between transmitting and receiving sections. For example, in the case of a display, it is possible to supply sufficient power for all power requirements of a display together with all signaling, such as data, timing and control signals. It is po

Problems solved by technology

Attaching this cable adds a significant cost in the manufacture of the display.

The increase in the complexity of the display system inevitably leads to a corresponding increase in the number of external connections which results in a bigger FPC connector.

However, products incorporating these display systems are becoming physically smaller in size and there is therefore pressure to find alternative methods of transmitting the signals to the display system.

If the bandwidth available in these systems is less than the signal bandwidth, then the signal will lose some information and can lead to erroneous decoding of the transmitted data.

However, the difficulty arises when an application requires both power and data to be transmitted wirelessly across the same wireless channel.

The implication is that it is more difficult to recover both power and data if the data signal has high bandwidth.

Increasing Q improves the power transferring capability of the system but reduces the overall bandwidth of the data that can be transmitted.

This makes the transmission of both power and high bandwidth data a very challenging problem.

A major drawback of this method is that the frequency at which the data bits ‘1 ’ and ‘0 ’ are transmitted should be highly stable.

This is because the high Q of each peak in the transfer function of FIG. 20 results in a locally narrow band system and any deviation of the signal components from these frequencies will completely corrupt the transmitted signal.

This is very difficult if the Q is made very high to allow sufficient power transfer.

Another drawback of the system is that only one element of the antenna transmits the signal.

However, for high power system requirements such as powering the backlight of an LC display, a single transmitting element would not supply sufficient power.

However, the system is only able to transmit sufficient power to supply the driver ICs 87 and 89.

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